console.time();
      var num = 0;
      for (var i = 0; i < 100000000; i++) {
        num += i;
      }
      console.log("num的值是",num);
      //发送num到引入的js里
      postMessage(num);//发送num到webworker.html里
      console.log(num);
      console.timeEnd();